package utils;

import android.text.InputFilter;
import android.text.Spanned;
import android.text.TextUtils;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Created by Simon on 2016/1/30.
 * 过滤用户输入只能为金额格式
 */
public class CashierInputFilter implements InputFilter {
    Pattern mPattern;

    //输入的最大金额
    private static final int MAX_VALUE = Integer.MAX_VALUE;
    //小数点后的位数
    private static final int POINTER_LENGTH = 2;

    private static final String POINTER = ".";

    private static final String ZERO = "0";

    public CashierInputFilter() {
        mPattern = Pattern.compile("([0-9]|\\.)*");
    }

    /**
     * @param source 新输入的字符串
     * @param start  新输入的字符串起始下标，一般为0
     * @param end    新输入的字符串终点下标，一般为source长度-1
     * @param dest   输入之前文本框内容
     * @param dstart 原内容起始坐标，一般为0
     * @param dend   原内容终点坐标，一般为dest长度-1
     * @return 输入内容
     */
    @Override
    public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
        String sourceText = source.toString();
        String destText = dest.toString();

        //验证删除等按键
        if (TextUtils.isEmpty(sourceText)) {
            return "";
        }

        Matcher matcher = mPattern.matcher(source);

        //已经输入小数点的情况下，只能输入数字
        if (destText.contains(POINTER)) {
            if (!matcher.matches()) {
                return "";
            } else {
                if (POINTER.equals(source)) {  //只能输入一个小数点
                    return "";
                }
            }

            //验证小数点精度，保证小数点后只能输入两位
            int index = destText.indexOf(POINTER);
            int length = destText.length() - index;

            if (length > POINTER_LENGTH) {
                return dest.subSequence(dstart, dend);
            }
        } else {
            //没有输入小数点的情况下，只能输入小数点和数字，但首位不能输入小数点和0
            if (!matcher.matches()) {
                return "";
            } else {
                if (POINTER.equals(source)) {
                    if (TextUtils.isEmpty(destText)) {
                        sourceText = "0.";
                    }
                }
                if (ZERO.equals(source)) {
                    if (!TextUtils.isEmpty(destText)) {
                        double value = parseMoney(destText);
                        if (value == 0) {
                            return "";
                        }
                    }

                }
            }
        }

        //验证输入金额的大小
        double sumText = parseMoney(destText + sourceText);
        if (sumText > MAX_VALUE || sumText == 0) {
            return dest.subSequence(dstart, dend);
        }

        return dest.subSequence(dstart, dend) + sourceText;
    }

    /**
     * 匹配money
     *
     * @return
     */
    private double parseMoney(String text) {
        if (TextUtils.isEmpty(text)) {
            return 0;
        }
        String result = null;
        //去除开始多余的0
        int length = text.length();
        int end = 0;
        for (int i = 0; i < length; i++) {
            String c = String.valueOf(text.charAt(i));
            if (!c.equals(ZERO)) {
                end = i;
                break;
            }
        }
        String substring = text.substring(end, length);
        //如果去0后，首字母为"."加上0
        if (!TextUtils.isEmpty(substring)) {
            if (substring.length() > 0) {
                char c = substring.charAt(0);
                if (c == '.') {
                    result = "0.";
                } else {
                    result = substring;
                }
            }
        }
        return Utils.parseDouble(result.replace(",", ""));
    }
}